1. Field of the Invention
This invention relates to a compact V-type internal combustion engine in which two banks are arranged in a V-shaped form and more particularly, to an improved arrangement of a V-type engine equipped with an auxiliary combustion chamber and with a common cam shaft for operating the valve operating mechanisms.
2. Description of the Prior Art
V-type internal combustion engines have been proposed in the prior art in which a left bank and a right bank are arranged in a V-shaped form. A typical arrangement of such V-type engines, as shown in FIG. 3a, comprises an injection pump (A) located inside the V-shaped between the two banks, injection nozzles (B) each projecting into the bank from the outside of the V-shape, intake manifolds (C) each connected to the bank from the inside thereof, exhaust manifolds (D) each connected to the bank from the outside thereof, a cam shaft (E), a crank shaft (F), and injection pipes (G) each connected between the injection pump and the injection nozzle. However, such V-type engines having the injection pump and the injection nozzle located at the opposite positions with respect to the bank require an elongated injection pipe for connection. This causes unfavorable fuel injection characteristics from the view point of exhaust smoke, gaseous emissions and performance.
In order to shorten the injection pipe, several different arrangements have also been proposed in the prior art. One such arrangement has the intake manifolds connected from a position outside of the V-shape and on the same side as the exhaust manifold to provide a space for projecting the injection nozzles to the banks from the inside thereof so as to locate the nozzles close to the injection pump (see FIG. 3b). However, this arrangement spoils the volumetric efficiency and output power and increases the width of the engine. Another arrangement has two cam shafts disposed outside the banks instead of a single cam shaft disposed inside the banks (see FIG. 3c). This increases the number of the structural parts and, in turn, increases the weight and cost of the engine. A further arrangement, which has two separated pumps disposed outside of the V-shape and close to the respective injection nozzles, also increases the weight and cost of the engine (see FIG. 3d ). Accordingly the prior art arrangements do not provide optimum performance of the engines within the limited conditions such as size, weight, cost or the like.